Effect of phosphatase treatment on the two-dimensional gel pattern of active caspases. Z-EK(bio)D-aomk treated cytosol from etoposide-treated HL-60 cells was incubated with 400 U λ phosphatase in the presence (A) or absence (B) of the inhibitor sodium orthovanadate, then subjected to analysis by two-dimensional PAGE. Black arrows point to caspases that disappear upon phosphatase treatment. (C) Indexing of the active caspases present in (A). Filled circles correspond to caspases that disappear upon phosphatase treatment. (D) Bar chart illustrating the relative abundance of the various species shown in (A) (average of three independent experiments, with the standard deviation indicated). Also shown is the nomenclature of the various active caspases detected in this experiment together with their corresponding isoelectric points. Species indicated by an asterisk (*) correspond to caspases that disappear upon dephosphorylation.